It is reckoned that in the UK, heating houses accounts for nearly 50% of the total energy use. Poor heating can render parts of dwellings virtually unusable, partly through discomfort due to cold and drafts and partly through the damage caused to contents through condensation, dampness, mould growth, etc. effectively reducing the house size because you can’t use parts of it. Couple this with rising energy costs and the danger of CO2Carbon dioxide is a gas which is given off when carbon based materials such as fossil fuels (coal, oil, and natural gas) are burned. It is called a greenhouse gas because it works like the glazing of a greenhouse and causes global warming pollution and there is every reason to put a lot of thought into the design of the heating system.

Unless you have a large source of free non-polluting heat such as geothermal then the best type of heating is the least. This means large amounts of insulation and airtightness and also good heating controls.

The main issues around heating which need to be considered are -

• heating calculations
• energy source / fuel types and boilers
• the role of passive solar heating
• energy harvesting
• is combined heat and power (CHP Combined heat and power - where the heat which is produced when electricity is generated is used within a heating system rather than wasted. This can happen at different levels - within a single house, a housing development, a town etc. ) an option?
• controls , thermostats and optimisers
• emitters (radiators, convectors etc) and sentience
• pipes / heating circuits and pumps
• domestic hot water

Other points may be important such as whether a heating circuit can be split or metered differently should the house be divided up differently in the future, say into two smaller flats. See Flexible design

The maintenance aspect of heating can be considerable with costs currently running around £200 p.a. for a gas boiler if you have insurance and do scheduled maintenance.

The subject of cooling in summer may have some bearing on the heating system

Fuel Cost

Nottingham Energy Partnership have an ENERGY COST COMPARISON page which compares the costs of various fuels taking into account the efficiencies of the respective boilers. (column ‘Pence per kWhkilowatt hour. This is a unit to measure an amount of energy. If you run your 30 kW gas boiler for 2 hours a day you use 60 kWh per day (after boiler efficiency)’).

Combined heat and power

This is mainly dealt with here because it is still an emerging technology. If you should decide to try it then you need to do several things

• estimate carefully the likely energy use of your house for both electricity and heating
• check you can do net meteringthis is a special type of electrical tariff which rewards you if you sell electricity you produce back into the national grid (effectively making your meter go backwards). see Energy harvesting
• get as much up-to-date information as you can from suppliers and ask to talk to some of their existing customers
• remember you might need to allow extra space for the boiler
• you may need space for a water accumulatorusually a large water tank used to store surplus heat (from say a wood fired boiler or thermal solar collector). see the page on Heat Stores
• try to contact other people who have a wider experience of CHP use

It is becoming possible to generate electricity from a wood stove at the same time as getting heat. The Austrian SPM company have integrated a Stirling engine into a wood pellet stove. It produces up to a kilowatt of electricity. It is not clear whether development is still ongoing with this product

Stirling engine generator

See also the Sunmachine wood pellet generator

Hearths

see also Chimneys

The Building RegulationsThese are the legal regulations which govern how a house is constructed. (not to be confused with Planning Permission which is about whether you are allowed to build the house at all or what it might look like) see Building Regulations) (Approved Document J) stipulate what type of hearth is required for various stoves and heaters and other issues such as combustibility of the surrounding areas. Chimneys are also covered by the regs and it should be noted that if a stainless steel twin wall fluepipe to conduct gas, typically ventilation air or boiler exhaust. see Flue is used then (depending on the manufacturer) the specification will vary between different types of fuel such as coal and wood.

Fluespipe to conduct gas, typically ventilation air or boiler exhaust. see more on Flues serving wood stoves have a tendency for tar to build up on the inside and then catch fire. This is more likely if the inside surface becomes cool due to the length of the flue or lack of insulation round the flue or burning damp wood. This is why a special type of flue is required for wood burning. It needs to be able to withstand quite a fierce fire which would never happen in a flue serving a gas fire.

Many stove suppliers and installers will give advice on this.

Very often you are forced to use a concrete hearth built into a floor and if the underside of this area is facing down into an unheated area such as a cellar then it is very important to insulate it heavily. Uninsulated, it will be a major heat loss downwards but if it is well insulated it can act as a heat store for any radiant or conducted heat coming off the appliance.

 

insulated hearth construction

Air supply to stoves

All combustion appliances require an air supply and wood burning stoves are no exception. As houses become more airtight, the correct design of air supply becomes more of an issue. Many stoves are now designed so that a combustion air supply pipe goes directly to the stove rather than the stove getting its air from the room. This also cuts down on cold drafts within the room.